Participants were randomly assigned to consume a no-alcohol control beverage (n = 30 [16 women]), an active placebo beverage (n = 33 [18 women]; 0.04 g/kg alcohol), or an alcohol beverage (n = 33 [15 women]; 0.80 g/kg alcohol; target peak breath alcohol concentration [BrAC] = .08%). Participants in the control condition were told that their beverage contained no alcohol; participants in the placebo and alcohol conditions were told that their beverage contained “a moderate amount of alcohol.” In these conditions, an experimenter ostensibly prepared a beverage containing a 5:1, tonic to vodka ratio. The placebo dose was achieved with diluted (10 proof) vodka (9 parts flattened tonic to 1 part 100-proof vodka, poured from a Smirnoff Blue Label® bottle) and tonic; the alcohol dose was achieved using 100-proof vodka and tonic, calculated based on total body water volume (estimated using age, gender, height, and weight) and the duration of the drinking period (15 min), using published formulas (see Curtin & Fairchild, 2003; Watson, 1989). Participants in the control group consumed a tonic-only beverage. Total beverage was isovolemic across conditions.
